Pseudomonas aeruginosa produces a fulminating corneal infection which is difficult to treat and often results in extensive corneal scarring and visual impairment. The overall objective of the proposed research is to elucidate the mechanism/s by which the bacterium causes the corneal destruction characteristic of P. aeruginosa corneal infections. The approach which will be taken to clarify this pathological process will be (a) to isolate the extracellular pseudomonal products which cause corneal damage, (b) to determine their physico-chemical properties, and (c) to define the mechanism/s by which they elicit corneal pathology. The cornea-damaging products will be isolated in homogeneous states by means of sequential (a) salt and organic solvent precipitation, (b) ion-exchange cellulose, molecular sieve, and adsorption chromatography, and (c) isoelectric focusing. The products will be examined for enzymatic activities and their sizes and chemical compositions determined. The last part of the proposed research will consist of experiments designed to determine the mechanism/s by which the products damage corneal tissue. These studies will involve: (a) light and electron microscopic examination of lesions produced by intracorneal injection of the products and (b) determining if the products can damage or kill polymorphonuclear leukocytes and corneal epithelial and endothelial cells, and cause them to liberate cornea-damaging substances.